DE112018000809T5 - tire - Google Patents

Abstract

In a pneumatic tire 1, an inner shoulder land portion (31) includes shoulder lug grooves (311) extending in the tire transverse direction. In addition, an inner second land portion (32) includes the continuous lug groove (321) extending in the tire transverse direction through the inner second land portion (32). A central land portion (33) includes a single narrow circumferential groove (331) extending in the tire circumferential direction and central lug grooves (332) opening at an end portion respectively to the vehicle width direction inner side edge portion of the central land portion (33) and terminate at the other end portion and communicate with a narrow circumferential groove (331). The shoulder lug groove (311), the through lug groove (321) and the central lug groove (332) form a single lug groove extending continuously from a ground contact edge (T) of the tire to an equatorial plane (CL) of the tire.

Description

Technical area

The invention relates to a pneumatic tire and, more particularly, to a pneumatic tire which can provide improved wet steering stability performance and ensure vehicle exterior noise performance.

State of the art

In pneumatic tires of the prior art, there is a need to achieve the noise performance and wet performance of the tire in a compatible manner. An example of such a prior art pneumatic tire relating to this need is the technology described in Patent Document 1.

Bibliography

• Patentdokument 1: JP 2013-52736 A

patent literature

• Patent Document 1: JP 2013-52736 A

Brief description of the invention

Technical problem

An object of the invention is to provide a pneumatic tire that can provide improved wet steering stability performance and ensure vehicle exterior noise performance.

the solution of the problem

• einen Anzeigeabschnitt für die Montagerichtung, der eine Montagerichtung des Luftreifens in Bezug auf ein Fahrzeug anzeigt;
• zwei oder mehr Hauptumfangsrillen, die in einem Bereich auf einer Innenseite in Fahrzeugbreitenrichtung einer Äquatorialebene des Reifens angeordnet sind und sich in Reifenumfangsrichtung erstrecken; und drei oder mehr Stegabschnitte, die durch die zwei oder mehr Hauptumfangsrillen definiert und ausgebildet sind;
• der in Fahrzeugbreitenrichtung am weitesten innen angeordnete Stegabschnitt ist als ein innerer Schulterstegabschnitt definiert, der auf der Äquatorialebene des Reifens angeordnete Stegabschnitt ist als ein zentraler Stegabschnitt definiert, und ein oder mehrere Stegabschnitte, die zwischen dem inneren Schulterstegabschnitt und dem zentralen Stegabschnitt angeordnet sind, sind als ein innerer zweiter Stegabschnitt definiert;
• der innere Schulterstegabschnitt umfasst eine Schulterstollenrille, die sich in Reifenquerrichtung erstreckt;
• der eine oder die mehreren inneren Schulterstegabschnitte umfassen eine durchgehende Stollenrille, die sich in Reifenquerrichtung durch den inneren Schulterstegabschnitt erstreckt;
• der zentrale Stegabschnitt umfasst eine einzige schmale Umfangsrille, die sich in Reifenumfangsrichtung erstreckt, und eine zentrale Stollenrille, die sich an einem Endabschnitt zu einem Randabschnitt des zentralen Stegabschnitts auf der Innenseite in Fahrzeugbreitenrichtung öffnet und an einem anderen Endabschnitt endet und mit der schmalen Umfangsrille in Verbindung steht; und
• die Schulterstollenrille, die durchgehende Stollenrille und die zentrale Stollenrille bilden eine einzige Verbindungsstollenrille, die sich durchgängig von einem Bodenkontaktrand des Reifens zur Äquatorialebene des Reifens hin erstreckt.

In order to achieve the object described above, a pneumatic tire according to an embodiment of the invention comprises:

• a mounting direction indicating portion indicating a mounting direction of the pneumatic tire with respect to a vehicle;
• two or more main circumferential grooves arranged in an area on an inside in the vehicle width direction of an equatorial plane of the tire and extending in the tire circumferential direction; and three or more land portions defined and formed by the two or more circumferential main grooves;
• the vehicle-width-direction-most land portion is defined as an inner shoulder land portion, the land portion disposed on the equatorial plane of the tire is defined as a central land portion, and one or more land portions disposed between the inner shoulder land portion and the central land portion are referred to as an inner second land portion defined;
• the inner shoulder land portion includes a shoulder lug groove extending in the tire transverse direction;
• the one or more inner shoulder land portions include a continuous lug groove extending in the tire transverse direction through the inner shoulder land portion;
• the central land portion includes a single narrow circumferential groove extending in the tire circumferential direction, and a central lug groove opening at an end portion to an edge portion of the central land portion in the vehicle width direction inside and terminating at another end portion and communicating with the narrow circumferential groove stands; and
• the shoulder lug groove, the continuous lug groove and the central lug groove form a single lug groove which extends continuously from a ground contact edge of the tire to the equatorial plane of the tire.

Advantageous effects of the invention

In the pneumatic tire according to an embodiment of the invention, the connection lug groove forms an efficient drainage channel from the central lug groove to the bottom contact edge of the tire. This has the advantage of improving the wet steering stability performance of the tire. In addition, the central lug groove communicates with the narrow circumferential groove of the central land portion and ends. Thus, the transmission of pattern noise to the outside in the vehicle width direction is suppressed. This is advantageous because the noise performance of the tire is improved.

list of figures

• 1 FIG. 10 is a cross-sectional view in a tire meridian direction illustrating a pneumatic tire according to an embodiment of the invention. FIG.
• 2 FIG. 11 is a plan view illustrating a tread surface of the in. FIG 1 illustrated pneumatic tire illustrated.
• 3 is an explanatory diagram that includes an in 2 illustrated tread pattern illustrated.
• 4 is an explanatory diagram showing an in 3 illustrated inner second web portion illustrated.
• 5 is an explanatory diagram that corresponds to the in 3 illustrated inner second web portion illustrated.
• 6 is an explanatory diagram that corresponds to the in 3 illustrated inner second web portion illustrated.
• 7 Fig. 10 is a graph showing the relationship between the width and the depth of a first tapered portion.
• 8th is an explanatory diagram showing an in 3 illustrated central web section illustrated.
• 9 is an explanatory diagram that corresponds to the in 3 illustrated central web section illustrated.
• 10 is an explanatory diagram that corresponds to the in 3 illustrated central web section illustrated.
• 11 is an explanatory diagram showing an in 2 illustrated lug groove illustrated.
• 12 is an explanatory diagram that includes the in 2 illustrated lug groove illustrated.
• 13 FIG. 12 is an explanatory diagram of a modified example of the embodiment of FIG 12 illustrated lug groove.
• 14 FIG. 12 is an explanatory diagram of a modified example of the embodiment of FIG 12 illustrated lug groove.
• 15 FIG. 13 is a table showing the results of performance tests of pneumatic tires according to embodiments of the invention. FIG.

Description of embodiments

Embodiments of the invention will be described below in detail with reference to the drawings. However, the invention is not limited to these embodiments. In addition, components of the embodiments include elements that are interchangeable while maintaining accordance with the invention; as well as obviously interchangeable elements. Moreover, the modified examples described in the embodiments can be combined as needed within the scope of protection obvious to a person skilled in the art.

tire

1 FIG. 10 is a cross-sectional view in a tire meridian direction illustrating a pneumatic tire according to an embodiment of the invention. FIG. The same drawing illustrates a cross-sectional view of a half region in the tire radial direction. Also, the same drawing illustrates a radial tire for a passenger car as an example of a pneumatic tire.

With reference to the same drawing, "cross section in a tire meridian direction" refers to a cross section of the tire along a plane including the tire rotation axis (not shown). Reference character CL denotes the equatorial plane of the tire and refers to a plane perpendicular to the tire rotation axis passing through the center of the tire in the direction of the tire rotation axis. "Tire transverse direction" refers to the direction parallel to the tire rotation axis. "Tire radial direction" refers to the direction perpendicular to the tire rotation axis.

Further, the inside in the vehicle width direction and the outside in the vehicle width direction are defined with respect to the vehicle width direction when the tire is mounted on the vehicle. In particular, the pneumatic tire closes 1 a mounting direction indicating section (not illustrated) indicating the mounting direction with respect to a vehicle. The mounting direction indicating portion is made of, for example, a mark or ridges on the sidewall portion of the tire. For example, the regulation requires 30 Economic Commission for Europe (ECE R30 ) that a mounting direction indicating portion is provided to a vehicle on the sidewall portion on the vehicle widthwise outer side when the tire is mounted on a vehicle.

The pneumatic tire 1 has a ring structure whose center is the tire rotation axis, and includes a pair of bead cores 11 . 11 , a pair of bead fillers 12 . 12 , a carcass layer 13 , a belt layer 14 , a tread rubber 15 , a pair of sidewall rubbers 16 . 16 and a pair of rim pad rubbers 17 . 17 a (see 1 ).

The pair of bead cores 11 . 11 has an annular structure formed of a tire bead wire made of steel or an organic fiber material wound around in the tire circumferential direction several times and forms cores of left and right bead portions. The pair of bead fillers 12 . 12 is from the pair of tire bead cores 11 . 11 disposed outwardly in the tire radial direction and forms the tire bead portions.

The carcass layer 13 has a single-layered structure consisting of a single carcass ply or a multi-layered structure consisting of a plurality of carcass plies, and extends between the left and right bead 11 . 11 in a toroidal shape, thereby forming the support structure for the tire. In addition, both end portions of the carcass layer 13 so bent back outwards in the tire transverse direction that they are around the bead cores 11 and the bead filler 12 are wound and fixed. The carcass ply (s) of the carcass ply 13 is made by performing a rolling process for coating rubber coated carcass cords of steel or an organic fiber material (e.g., aramid, nylon, polyester, rayon, or the like). The carcass ply (ply) has a carcass angle (defined as the inclination angle of the longitudinal direction of the carcass cords with respect to the tire circumferential direction) in an amount ranging from 80 degrees to 95 degrees.

The belt layer 14 is a multi-layered structure that is a pair of crossbelt 141 . 142 and a belt cover 143 and is around the outer circumference of the carcass ply 13 arranged. The pair of cross girdles 141 . 142 is produced by performing a rolling process on coating rubber-coated belt cords made of steel or an organic fiber material. The crossbelt 141 . 142 have a belt angle with an amount in the range of 20 degrees to 55 degrees. The pair also has crossbelt 141 . 142 Belt angle (defined as the inclination angle of the longitudinal direction of the belt cords with respect to the tire circumferential direction) of opposite sign, and the belts are layered so that the longitudinal directions of the belt cords cross each other (ie, cross-ply structure). In addition, the belt cover 143 by coating belt cords made of steel or an organic fiber material with a coating rubber. The belt cover 143 has a belt angle with an amount in the range of 0 degrees to 10 degrees. Further, the belt cover 143 For example, a strip material obtained by coating one or more belt cords with a coating rubber and repeatedly spirally winding the strip material around the outer peripheral surface of the cross belts 141 . 142 is formed in the tire circumferential direction.

The tread rubber 15 is outside the carcass layer 13 and the belt layer 14 arranged in the tire radial direction and forms a tread portion of the tire. The pair of sidewall rubbers 16 . 16 is from the carcass layer 13 arranged in the tire transverse direction outside and forms a left and a right side wall portion. The pair of wheel rim upholstery rubbers 17 . 17 is from the left and right tire bead core 11 . 11 and the bent-back portions of the carcass ply 13 arranged in the tire radial direction inside. The pair of wheel rim upholstery rubbers 17 . 17 forms the contact surfaces of the left and right bead section with the rim flanges.

Tread pattern

2 FIG. 11 is a plan view illustrating a tread surface of the in. FIG 1 illustrated pneumatic tire illustrated. The same drawing illustrates a tread pattern for an all-season tire. With reference to the same drawing, "tire circumferential direction" refers to the direction that rotates about the tire rotation axis. The reference number T denotes a ground contact edge and the dimension symbol TW denotes a tire ground contact width.

As in 2 shown is the pneumatic tire 1 in the tread portion having a plurality of circumferential main grooves 21 to 24 provided in the tire circumferential direction, and a plurality of land portions 31 to 35 passing through the main circumferential grooves 21 to 24 are defined.

"Main groove" refers to a groove in which a wear indicator according to JATMA is to be provided and which typically has a groove width of 4.0 mm or more and a groove depth of 6.5 mm or more. "Stud groove" (described below) refers to a lateral groove extending in a tire transverse direction and typically having a groove width of 1.0 mm or more and a groove depth of 3.0 mm or more. A lug groove opens when the tire comes in contact with the ground and acts as a groove. "Slat" (described below) refers to a cut formed in a tread-contacting surface and typically having a sipe width of less than 1.0 mm and a sipe depth of 2.0 mm or more so that the sipe closes when the sipe contacts Tire comes in contact with the ground.

The groove width is the maximum distance between the left and right groove walls on the tread contact surface and is measured when the tire is mounted on a given rim and filled to the predetermined internal pressure and is in an unloaded state. In configurations in which the land portions include recessed portions or chamfered portions on the edge portions thereof, the groove width is measured with reference to the intersections where, when viewed in a cross-sectional view perpendicular to the groove longitudinal direction, the tread contact surface and extension lines of the groove walls meet. In addition, in a configuration in which the grooves extend in a zigzag or wave-like manner in the tire circumferential direction, the Groove width measured using the centerline of the amplitude of the groove walls as a measuring point.

The groove depth is the maximum distance from the tread contact surface to the groove bottom and is measured when the tire is mounted on a given rim and filled to the predetermined internal pressure and is in an unloaded condition. In addition, in a configuration in which the grooves include an uneven portion or fins on the groove bottom, the groove depth is measured excluding these portions.

The sipe width is measured as the maximum opening width of the sipe at the ground contacting surface of the land portion when the tire is mounted on a predetermined rim, inflated to the predetermined internal pressure and in an unloaded state.

The ground contacting surface of a tire is defined as a contact surface between a tire and a flat plate when the tire is mounted on a given rim, inflated to the predetermined internal pressure, placed vertically on the flat plate in a static state, and loaded according to the predetermined load is loaded.

"Specified rim" refers to a "applicable rim" as defined by the Japan Automobile Tire Manufacturers Association Inc. (JATMA), a "Design Rim" as defined by the Tire and Rim Association , Inc. (TRA, Tire and Rim Association) or a "Measuring Rim" as defined by the European Tire and Rim Technical Organization (ETRTO, European Tire and Wheel Wheels Organization). In addition, "given internal pressure" refers to a "maximum air pressure" as defined by JATMA, to the maximum value in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" as defined by the TRA or to " INFLATION PRESSURES "(tire pressures) as defined by the ETRTO. In addition, "given load" refers to a "maximum load capacity" as defined by JATMA, the maximum value in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" as defined by the TRA or "LOAD CAPACITY "(Load capacity) as defined by the ETRTO. However, in the case of JATMA for a passenger tire, the given internal pressure is an air pressure of 180 kPa, and the predetermined load is 88% of the maximum load capacity.

For example, in the configuration of 2 the inside area and the outside area in the vehicle width direction respectively have two main circumferential grooves 21 . 22 ; 23 . 24 , For example, these are the major circumferential grooves 21 to 24 arranged so that they have substantially a left-right symmetry around the equatorial plane CL of the tire. Five bridge sections 31 to 35 are through the main circumferential grooves 21 to 24 Are defined. In addition, there is a bridge section 33 on the equatorial plane CL of the tire.

However, no such limitation is intended and five or more major circumferential grooves may be arranged, or the major circumferential grooves may be arranged asymmetrically with respect to the equatorial plane CL of the tire (not illustrated).

Of the two or more main circumferential grooves, which are arranged in an area passing through the equatorial plane CL of the tire is demarcated (including a main circumferential groove in the equatorial plane CL of the tire) are the circumferential main grooves in the tire transverse direction 21 . 24 defined as outermost circumferential major grooves. The outermost circumferential main groove becomes in each of the left and right side regions of the equatorial plane CL of the tire. The outermost circumferential main groove 21 in the inner portion of the vehicle width direction is also referred to as an inner outermost circumferential main groove, and the outermost circumferential main groove 24 in the outer portion of the vehicle width direction is referred to as an outer outermost circumferential main groove. The distance from the equatorial plane CL of the tire to the left and right outermost circumferential main grooves 21 . 24 (in the drawing, the dimension symbol is omitted) ranges from 20% to 35% of the ground contact width TW of the tire.

The ground contact width TW of the tire is measured as the maximum linear distance in the tire axial direction of a contact surface between the tire and a flat plate when the tire is mounted on a given rim, inflated to a predetermined internal pressure, placed vertically on the flat plate in a static state, and loaded , which corresponds to the predetermined load is loaded.

The ground contact edge of the tire T is defined as the position of maximum width in the tire axial direction of the contact surface between the tire and a flat plate when the tire is mounted on a given rim, inflated to the predetermined internal pressure, placed vertically on the flat plate in a static state, and loaded with a load corresponds to the predetermined load, is loaded.

In addition, the bridge sections 31 . 35 arranged outward in the tire transverse direction and through the outermost circumferential main grooves 21 . 24 are defined as shoulder land sections. The shoulder bridge sections 31 . 35 are web portions which are outermost in the tire transverse direction on the ground contact edges T of the tire are arranged. In addition, the shoulder land section 31 which is disposed in the vehicle width direction inner region, defined as an inner shoulder land portion, and the shoulder land portion 35 That is arranged in the vehicle-width-direction outer region is defined as an outer shoulder land portion.

The bridge section 33 on the equatorial plane CL of the tire (see 2 ), or the left and right land portions defined by a major circumferential groove located on the equatorial plane CL of the tire (not illustrated) are defined as a central web portion.

In addition, all web sections 32 . 34 between the shoulder ridge sections 31 . 35 and the central bridge section 33 are arranged, defined as second web portions. Also, the second bridge section 32 which is disposed in the vehicle width direction inner region defined as an inner second land portion, and the second land portion 34 is disposed in the vehicle-width-direction outer region is defined as an outer second land portion.

Second inner dock section

3 is an explanatory diagram that illustrates the in 2 illustrated tread pattern illustrated. The same drawing illustrates an enlarged view of the inner second land portion 32 and the central footbridge section 33 , 4 to 6 are explanatory diagrams corresponding to those in 3 Illustrate illustrated inner second web portion. 4 is a schematic view showing a continuous lug groove 321 and beveled sections 323 . 324 the inner second web portion 32 illustrated. 5 is a cross-sectional view in the groove longitudinal direction of the continuous lug groove 321 , 6 is a cross-sectional view along the line A in 4 ,

As in 3 shown includes the inner second land portion 32 a plurality of continuous lug grooves 321 and a plurality of fins 322 ,

The continuous lug grooves 321 extend in the tire transverse direction through the inner second web portion 32 , In the in 3 illustrated configuration, the continuous lug grooves 321 an arcuate shape with a gentle curvature and tilt with their extension to the ground contact edge T of the tire slightly in the tire circumferential direction. In addition, the entire continuous lug groove 321 with a predetermined angle of inclination θ1 (please refer 4 ) inclined with respect to the tire circumferential direction. The angle of inclination θ1 is in the range of 40 degrees ≤ θ1 ≤ 70 degrees. Thus, the drainage function of the continuous lug grooves 321 ensured.

The inclination angle of the entire lug groove is measured as an angle between a straight line connecting the centers of both ends of the lug groove and the tire circumferential direction.

A groove width W g1 (please refer 4 ) of the continuous lug groove 321 is in the range of 1.0 mm ≤ Wg1 ≤ 4.0 mm and opens when the tire comes in contact with the ground.

Especially in the tread pattern of 2 are the continuous lug grooves 321 narrow grooves, and the groove width W g1 the continuous lug grooves 321 and a groove width wm2 the main circumferential groove 22 on the side of the equatorial plane CL of the tire, the inner second web portion 32 have defined, have the ratio 0.10 ≤ Wg1 / Wm2 ≤ 0.40. In addition, the groove width is W g1 the continuous lug grooves 321 preferably in the range Wg1 ≤ 2.5 mm and more preferably in the range Wg1 ≤ 1.9 mm. Thus, the groove width W g1 the continuous lug groove 321 set appropriately.

Also have a groove depth hg1 the continuous lug grooves 321 and a groove depth Hm of the main circumferential groove 22 on the side of the equatorial plane CL of the tire, the inner second web portion 32 preferably, the ratio 0.60 ≦ Hg1 / Hm ≦ 0.90. Thus, the groove depth hg1 the continuous lug groove 321 set appropriately, and the noise performance and the wet steering stability performance of the tire are ensured.

As in 5 illustrates the continuous lug groove 321 a constant depth at the central portion of the inner second land portion 32 on. The continuous lug groove 321 includes a partially raised lower section 3211 on the left and right edge portions of the inner second land portion 32 , The rigidity of the inner second web portion 32 gets through these raised floor sections 3211 elevated.

The slats 322 are each between in the tire circumferential direction adjacent through lug grooves 321 . 321 arranged and extend in the tire transverse direction through the inner second bridge section 32 , In the configuration of 3 becomes the inner second land portion 32 in the tire circumferential direction through the plurality of continuous lug grooves 321 divided, whereby a plurality of blocks is formed (the reference numeral is omitted in the drawings). The blocks each contain a lamella 322 , In addition, the lamella points 322 an arcuate shape with a gentle curvature and extending parallel to the continuous lug groove 321 , In addition, a lamella 322 between the adjacent continuous lug grooves 321 . 321 and the ground contact area of a block is substantially divided into two equal sections in the tire circumferential direction. In this way, the rigidity of the block is determined by the lamella 322 made suitable, and the rigidity of the lamella 322 divided portion of the block is made uniform.

In addition, the continuous lug grooves 321 and the slats 322 arranged at a predetermined distance in the tire circumferential direction. In particular, a unit pattern consisting of a set becomes a continuous lug groove 321 and a lamella 322 contains repeatedly arranged in the tire circumferential direction. In addition, a pitch distance variation structure is used, and a unit pattern having plural kinds of pitch distances P (Pa, Pb,...) Is periodically arranged in the tire circumferential direction. In a typical pneumatic tire, three to seven kinds of pitch distances are used. With such a pitch distance structure pattern, the pattern noise caused by the arrangement of the lug grooves, fins and the like is reduced and the noise performance of the tire is improved.

Besides, as in the 3 to 6 illustrates includes the inner second web portion 32 the first bevelled section 323 and the second beveled portion 324 ,

The first beveled section 323 and the second beveled section 324 are at the left and right edge portion of one of the continuous lug grooves 321 educated. In addition, the first beveled section opens 323 at an end portion to the edge portion on the side of the ground contact edge of the tire T the inner second web portion 32 and terminates at the other end portion at a central portion in the tire transverse direction of the inner second land portion 32 , The second bevelled section 324 opens at an end portion to the edge portion on the side of the equatorial plane CL the tire of the inner second web portion 32 and terminates at the other end portion at a central portion in the tire transverse direction of the inner second land portion 32 ,

The chamfered portions are defined as a portion connecting the intersection portion of adjacent surfaces over a flat surface (eg, a corner bevel) or a curved surface (for example, a rounded chamfer). Thus, the chamfered portion is different from a recess portion in which a land portion is cut to form a step. As in 5 here are the first beveled section 323 and the second beveled section 324 Corner bevels, and the intersection portion of the road contact surface of the inner second land portion 32 and the groove wall surface of the continuous lug groove 321 (ie the edge portion of the continuous lug groove 321 ) is connected across a plane.

For example, in the configuration of 3 , have the first beveled section 323 and the second beveled section 324 a long structure that extends along the edge portion of the continuous lug groove 321 extends, and are on both sides of the continuous lug groove 321 arranged diagonally opposite each other. In addition, the first beveled portion extend 323 and the second beveled section 324 from an obtuse corner portion of the block passing through the continuous lug groove 321 is defined, along the edge portion of the continuous lug groove 321 and terminate at a central portion in the groove longitudinal direction of the continuous lug groove 321 , Thus, the first chamfered section 323 or the second beveled section 324 at the left and right edge portions of the continuous lug groove 321 only in either the left or right portion of the inner second land portion 32 educated. In addition, the other edge portion is the chamfered portion 323 facing; 324 has a simple structure that does not include other chamfered portions, notches, fin opening portions, or the like.

It should be noted, however, that no such limitation is intended and, for example, a small beveled portion (not illustrated) may be formed in a corner portion at an acute angle of a block passing through the continuous lug groove 321 is defined in order to suppress damage to the corner section. Such a small chamfered portion generally has a width and depth of not more than 4.0 mm.

In the configuration described above, (1) includes the continuous lug groove 321 the inner second web portion 32 the beveled sections 323 . 324 at the left and right edge portions, and thus the groove volume of the continuous lug groove becomes 321 to the bevelled sections 323 . 324 increased. Thus, the drainage characteristics of the inner second land portion become 32 improves and the wet performance of the tire is improved. In particular, in a configuration where the groove volume of the continuous lug groove is 321 over the chamfered sections 323 . 324 is increased, the rigidity of the inner second web portion 32 larger than that of a configuration in which the groove volume of the lug groove is enlarged over the recess portion. In this way, the dry steering stability performance and the wet steering stability performance of the tire are ensured.

In addition, (2) is the ground contact surface of the block passing through the continuous lug grooves 321 is defined as compared with a configuration in which the chamfered portion is formed in the entire area of the peripheral portion of the lug groove. In this way, the dry steering stability performance and the wet steering stability performance of the tire are ensured. Additionally ( 3 ) are the first beveled section 323 and the second beveled section 324 in the left and right areas of the inner second web section 32 arranged in the tire transverse direction. Compared with a configuration where the first beveled section 323 and the second beveled section 324 Both are arranged in a region, thus the rigidity of the inner second web portion 32 made uniform in the tire transverse direction. In this way, the dry steering stability performance and the wet steering stability performance of the tire are ensured. In addition, (4) is the first bevelled portion 323 and the second beveled section 324 at the left and right edge portions of the continuous lug groove 321 arranged. Thus, the rigidity of the front and rear blocks, through the continuous lug groove 321 are defined, compared to a configuration in which the first beveled section 323 and the second beveled section 324 both on either the left or right edge portion of the continuous lug groove 321 are arranged, evenly made. In this way, the dry steering stability performance and the wet steering stability performance of the tire are ensured.

Also meet in 4 a width W1 the inner second web portion 32 , an extension distance D1 the first beveled section 323 in the tire transverse direction and an extension distance D2 of the second beveled section 324 In the tire transverse direction, preferably, the ratios 0.40 ≦ D1 / W1 ≦ 0.60 and 0.40 ≦ D2 / W1 ≦ 0.60, and more preferably the ratios 0.45 ≦ D1 / W1 ≦ 0.55 and 0.45 ≦ D2 / W1 ≤ 0.55. In this way, the end portion positions of the chamfered portions 323 . 324 in the central portion of the inner second land portion 32 disposed in the tire transverse direction, and the rigidity of the left and right portions of the inner second land portion 32 in the tire transverse direction is designed accordingly uniform.

Under the conditions described above meet the width W1 the inner second web portion 32 , the extension distance D1 the first beveled section 323 in the tire transverse direction and the extension distance D2 of the second beveled section 324 in the tire transverse direction, the ratio -0.20 ≦ {W1 - (D1 + D2)} / W1 ≦ 0.20. In the configuration of 4 are the first beveled section 323 and the second beveled section 324 close to each other in the central portion of the second land portion 32 is arranged without overlapping in the tire transverse direction, and the above-described ratio is in the range of 0 ≦ {W1 - (D1 + D2)} / W1 ≦ 0.10.

The width of the land portion is measured as the tire transverse direction distance between the measuring points of the groove width of the left and right circumferential main grooves defining the land portion when the tire is mounted on a predetermined rim, inflated to the predetermined internal pressure, and unloaded. In addition, the width of the shoulder land portion is measured as the distance in the tire transverse direction between the measuring point of the groove width of the outermost circumferential main groove and the ground contacting edge of the tire.

In addition, in the 4 and 6 the groove width W g1 the continuous lug groove 321 and the circumferential width Wc1 ' the first beveled section 323 at an intermediate point in the tire transverse direction of the first chamfered portion 323 preferably the ratio 0.50 ≦ Wc1 '/ Wg1 ≦ 2.00. In this way, the wet performance of the tire can be improved and the rigidity of the web section 32 can be maintained. Additionally lies in the configuration of 4 the above-described ratio Wc1 '/ Wg1 in the range of 1.05 ≦ Wc1' / Wg1 ≦ 1.75, and the circumferential width Wc1 ' the first beveled section 323 is set to be larger than the groove width W g1 the continuous lug groove 321 is. In such a configuration, the inclination of the first beveled portion is 323 gently. Thus, the wet performance of the tire can be improved efficiently, and the change in the rigidity of the blocks can be minimized.

Similarly, the groove width W g1 the continuous lug groove 321 and a circumferential width Wc2 ' of the second beveled section 324 at an intermediate point in the tire transverse direction of the second tapered portion 324 preferably the ratio 0.50 ≦ Wc2 '/ Wg1 ≦ 2.00. In particular, in the configuration of 4 the ratio Wc2 '/ Wg1 described above is set in the range 1.20 ≦ Wc2' / Wg1 ≦ 2.00.

The circumferential width of the chamfered portion is defined as the length in the tire circumferential direction of the chamfered portion at the midpoint between both end portions of the chamfered portion in the tire transverse direction (see FIG 4 ). Specifically, in a tire-circumferential direction cross-sectional view at the above-described center point, the circumferential width of the tapered portion is measured using the intersection between the extension line of the road contact surface of the land portion and the extension line of the groove wall of the groove as a measurement point (see FIG 6 ).

Also in the configuration of 2 are, as described above, the continuous lug grooves 321 in the tire circumferential direction with a plurality of kinds of pitch distances P (Pa, Pb, ...) (see FIG 3 ). Also, the groove width W g1 the continuous lug grooves 321 at each pitch (see 4 ) is constant regardless of the pitch distance. The circumferential width Wc1 ' the first beveled section 323 and the circumferential width Wc2 ' of the second beveled section 324 increase and decrease in proportion to the pitch distance. Accordingly, at a pitch with a large pitch pitch, the circumferential width becomes Wc1 , The first bevelled section 323 and the circumferential width Wc2 ' of the second beveled section 324 adjusted so that they are tall. In such a configuration, the groove width is W g1 the continuous lug grooves 321 constant at each pitch, and in that the continuous lug groove 321 has a small groove width Wg1 (1.0 mm ≦ Wg1 ≦ 2.5 mm), the effect of improving the noise performance is achieved and the wet steering stability performance of the tire can be effectively ensured.

In addition, in 5 the groove depth hg1 the continuous lug groove 321 and a maximum depth Hc1_max the first beveled section 323 Preferably, the ratio 0.10 ≦ Hc1_max / Hg1 ≦ 0.40 and more preferably the ratio 0.13 ≦ Hc1_max / Hg1 ≦ 0.30. In this way, a depth HC1 the first beveled section 323 made suitable.

The maximum depth of the chamfered portion is measured as the groove depth direction distance from the road contact surface of the land portion to the maximum depth position of the chamfered portion.

7 Fig. 12 is a graph showing the relationship between the width and the depth of the first tapered portion. The same illustration shows the groove width Wg1 and the depth hg1 the continuous lug groove 321 at positions in the tire transverse direction; and the width Wc1 ' and the depth HC1 the first beveled section 323 ,

As in 4 is shown has the terminal end portion of the first tapered portion 323 in the middle section of the inner second web section 32 a shape that in terms of the circumferential width Wc1 ' gradually decreases. In particular, the first beveled section closes 323 a fan-shaped Abschlussendabschnitt, and the circumferential width Wc1 ' the first beveled section 323 takes from before the closing position to the equatorial plane CL of the tire gradually down to zero. Thus, the ground contacting surface is at the central portion of the inner second land portion 32 ensured, and the wet steering stability performance of the tire is ensured. In addition, the depth decreases HC1 (please refer 5 ) of the first beveled portion 323 gradually decreasing to zero in the direction toward the equatorial plane CL of the tire at or near the end portion. It should be noted that the circumferential width Wc2 ' and the depth Hc2 of the second beveled section 324 also the same configuration as the first beveled section 323 have (see 4 and 5 ).

As in 7 illustrates, takes the circumferential width Wc1 'the first beveled section 323 at the Edge portion of the inner second web portion 32 near the ground contact edge T of the tire (see 4 ). In this way, the effect of improving the drainage properties of the continuous lug groove becomes 321 over the first beveled section 323 elevated. The depth HC1 the first beveled section 323 is even at the edge portion of the inner second land portion 32 on the side of the ground contact margin T of the tire is constant (see 5 ). In this way, a decrease in the rigidity of the edge portion of the inner second land portion 32 caused by the formation of the first beveled section 323 caused, suppressed.

Besides, as in 7 illustrates the circumferential width Wc1 ' the first beveled section 323 preferably monotone from the terminal end portion of the first beveled portion 323 to the ground contact margin T of the tire towards (see 4 ). In particular, as in 7 illustrates the circumferential width Wc1 ' the first beveled section 323 from the end section on the side of the equatorial plane CL the tire of the first beveled portion 323 gradually increases, is in the middle section of the first beveled section 323 constant and takes on the edge portion of the inner second web portion 32 on the side of the ground contact margin T of the tire too. In this way, the groove volume of the continuous lug groove decreases 321 from the inner portion of the inner second land portion 32 to the ground contact margin T of the tire, and the effect of improving the drainage characteristics of the continuous lug groove 321 over the first beveled section 323 will be raised.

It should be noted that in the configuration described above, the circumferential width Wc1 ' the first beveled section 323 in the middle portion of the first tapered portion 323 is constant. However, no such limitation is intended and the circumferential width Wc1 ' the first beveled section 323 can be from the end section on the side of the equatorial plane CL of the tire to the edge portion on the side of the ground contact edge T the tire of the inner second web portion 32 (not illustrated) gradually increase gradually.

Central bridge section

8th to 10 are explanatory diagrams corresponding to those in 3 illustrated central web section represent. 8th Fig. 10 is a schematic view showing an example of a narrow circumferential groove 331 , a central lug groove 332 and a beveled section 334 of the central footbridge section 33 illustrated. 9 is a cross-sectional view towards the central lug groove 332 , 10 is a cross-sectional view along the line B in 8th ,

As in 3 shown includes the central web section 33 a narrow circumferential groove 331 , a plurality of the central lug grooves 332 and a plurality of fins 333 ,

The narrow circumferential groove 331 extends continuously in the tire circumferential direction and is in the central portion of the central land portion 33 arranged. In addition, a distance Ds from the edge portion of the central land portion 33 on the inside in the vehicle width direction to the groove center line of the narrow circumferential groove 331 and a width W2 of the central footbridge section 33 Preferably, the ratio 0.25 ≦ Ds / W2 ≦ 0.50, and more preferably the ratio 0.30 ≦ Ds / W2 ≦ 0.45. Thus, the position of the narrow circumferential groove becomes 331 made suitable and the wet performance of the tire is improved.

In addition, in the configuration of 2 the width W2 of the central footbridge section 33 and the ground contact width TW of the tire is 0.10 ≦ W2 / TW ≦ 0.30. Thus, the function of the central web section 33 suitably ensured.

Additionally, in the configuration of 2 the central bridge section 33 in the equatorial plane CL of the tire, and how in 8th illustrates, is the narrow circumferential groove 331 on the inner side of the vehicle width direction of the equatorial plane CL of the tire. Accordingly, the narrow circumferential groove 331 with respect to the equatorial plane of the tire CL offset on the inner side of the vehicle width direction. In this way, the drainage function by the narrow circumferential groove 331 is improved.

In addition, in 8th a groove width Ws of the narrow circumferential groove 331 of the central footbridge section 33 and the groove width wm2 the main circumferential groove 22 on the inside of the vehicle width direction, the central web section 33 preferably, the ratio 0.20 ≦ Ws / Wm2 ≦ 0.50, and more preferably the ratio 0.20 ≦ Ws / Wm2 ≦ 0.35. In addition, the groove width is Ws the narrow circumferential groove 331 preferably in the range of 1.0 mm ≦ Ws ≦ 3.0 mm, and more preferably in the range of 1.5 mm ≦ Ws ≦ 2.5 mm. Thus, the groove width Ws becomes the narrow circumferential groove 331 made suitable.

Besides, in 9 a groove depth Hs of the narrow circumferential groove 331 and the groove depth Hm of the main circumferential groove 22 on the inner side of the vehicle width direction, the central web portion 33 preferably, the ratio 0.60 ≦ Hs / Hm ≦ 0.90. Thus, the groove width W g1 the continuous lug groove 321 set appropriately.

As in 3 illustrated, the central lug grooves open 332 each at an end portion to the edge portion on the inner side of the vehicle width direction of the central land portion 33 and end at the other end portion and stand with the narrow circumferential groove 331 in connection. The central lug grooves 332 are on extension lines of the continuous lug grooves 321 the inner second web portion 32 arranged. Thus, the central lug grooves 332 inclined in the same direction as the continuous lug grooves 321 the inner second web portion 32 ,

In 8th is a tilt angle θ2 the central lug groove 332 with respect to the tire circumferential direction in the range of 30 degrees ≦ θ2 ≦ 60 degrees. Thus, the drainage function of the central lug groove 332 ensured.

A groove width Wg2 the central lug groove 332 is set in the same way as the groove width W g1 the continuous lug grooves 321 the inner second web portion 32 , Especially in the tread pattern of 2 are the central lug grooves 332 narrow grooves, and the groove width Wg2 the central lug groove 332 and the groove width wm2 the main circumferential groove 22 on the side of the ground contact edge T of the tire, which is the central web portion 33 have the ratio 0.10 ≤ Wg2 / Wm2 ≤ 0.40. In addition, the groove width is Wg2 the central lug groove 332 preferably in the range of 1.1 mm ≦ Wg2 ≦ 2.5 mm, and more preferably in the range of 1.2 mm ≦ Wg2 ≦ 1.9 mm. Thus, the groove width Wg2 the central lug groove 332 set appropriately. In other words, the drainage function becomes the central lug groove 332 ensured by the lower limit described above. In addition, with the upper limit described above, the groove width becomes Wg2 the central lug grooves 332 adjusted so that she is small. Thus, the groove area of the central land portion becomes 33 is reduced and the noise performance and the wet steering stability performance of the tire are improved.

Besides, in 9 a groove depth hg2 the central lug groove 332 and the groove depth Hm of the main circumferential groove 22 on the side of the ground contact edge T of the tire, which is the central web portion 33 preferably, the ratio 0.60 ≦ Hg2 / Hm ≦ 0.90. Thus, the groove depth becomes hg2 the central lug groove 332 set appropriately, and the noise performance and the wet steering stability performance of the tire are ensured.

Besides, in 9 the groove depth Hs of the narrow circumferential groove 331 and the groove depth hg2 the central lug groove 332 preferably, the ratio 0.75 ≦ Hs / Hg2 ≦ 0.95. The extension length of the narrow circumferential groove 331 is larger than that of the central lug grooves 332 , which results in a large impact on the groove volume. Here, the groove depth Hs becomes the narrow circumferential groove 331 adjusted so that they are smaller than the groove depth hg2 the central lug groove 332 is. In this way, deterioration of the noise performance is suppressed.

Besides, as in 9 illustrates the central lug groove 332 at the edge portion of the central web portion 33 on the inside in the vehicle width direction deepest and gradually flattening towards the equatorial plane CL of the tire, while at the connecting portion with the narrow circumferential groove 331 is flattened. Also contains the central lug groove 332 no partially raised floor section.

The slats 333 are between central lug grooves 332 . 332 disposed adjacent in the tire circumferential direction. The slats 333 each open at an end portion to the edge portion of the central web portion 33 on the inside in the vehicle width direction and terminate at the other end portion and stand with the narrow circumferential groove 331 in connection. In addition, the central lug grooves 332 and the slats 333 arranged at a predetermined distance in the tire circumferential direction. In the configuration of 3 is the central bridge section 33 in the tire transverse direction through the narrow circumferential groove 331 divided, and the area of the divided central web section 33 on the outside in the vehicle width direction is in the tire circumferential direction through the central lug grooves 332 divided, whereby a plurality of blocks is formed (reference number is omitted in the drawings). Each block contains a lamella 333 , The slats 333 extend parallel to the central lug grooves 332 , There is also a lamella 333 between the adjacent central lug grooves 332 . 332 and the ground contact area of a block is substantially divided into two equal sections in the tire circumferential direction. Thus, the block rigidity is made uniform.

As in the 3 and 8th to 10 illustrates, the central web section closes 33 the third beveled section 334 on.

The third beveled section 334 is at an edge portion of the central lug groove 332 educated. In addition, the third beveled section opens 334 at an end portion to the edge portion of the central land portion 33 on the side of the inner second land portion 32 and terminates at the other end portion at a central portion in the groove longitudinal direction of the central lug groove 332 , In this way, the groove volume of the central lug grooves 332 through the third beveled section 334 increases and the drainage properties of the web section 32 will be improved.

For example, in the configuration of 3 the third bevelled section 334 from a corner portion at an obtuse angle of a block passing through the narrow circumferential groove 331 and the central lug groove 332 is defined along the edge portion of the central lug groove 332 and terminates at a central portion in the groove longitudinal direction of the central lug groove 332 , Thus, the third bevelled portion 334 only in an area on the left or right edge of the central lug groove 332 educated. In addition, the other edge portion facing the third tapered portion 334 facing, a planar structure containing no other beveled portions, notches, louver opening portions or the like.

It should be noted, however, that no such limitation is intended and, for example, a small beveled portion (not illustrated) may be formed in a corner portion at an acute angle of a block passing through the narrow circumferential groove 331 and the central lug groove 332 is defined in order to suppress damage to the corner section.

In addition, in the configuration of 3 the third bevelled section 334 of the central footbridge section 33 on the same side in the tire circumferential direction as the first chamfered portion 323 the inner second web portion 32 educated. In other words, the central lug grooves 332 of the central footbridge section 33 on extension lines of the continuous lug grooves 321 the inner second web portion 32 arranged to form a lug groove. The first beveled section 323 and the second beveled section 324 the inner second web portion 32 and the third beveled section 334 of the central footbridge section 33 are alternately left and right along the lug groove in the direction of the equatorial plane CL of the tire. Thus, the rigidity balance between the inner second land portion 32 and the central bridge section 33 made suitable.

Additionally lies in 8th an extension distance D3 the third beveled section 334 in the tire transverse direction, preferably in a range of 30% to 70% of an extension length of the central lug groove 332 in the tire transverse direction (the dimension symbol is omitted in the drawings). Thus, the position of the terminal end portion of the third tapered portion becomes 334 made suitable.

In addition, in the 8th and 10 the groove width Wg2 the central lug groove 332 and a circumferential width wc3 'the third beveled section 334 at an intermediate point in the tire transverse direction of the third tapered portion 334 preferably the ratio 0.50 ≦ Wc3 '/ Wg2 ≦ 2.00. It is also in the configuration of 8th the above-described ratio Wc3 '/ Wg2 in the range of 1.05 ≦ Wc3' / Wg2 ≦ 1.75, and the circumferential width wc3 ' the third beveled section 334 is set to be larger than the groove width Wg2 the central lug groove 332 is. In this way, the inclination of the third beveled portion 334 low. Thus, the wet performance of the tire can be improved efficiently, and the change in the rigidity of the blocks can be minimized.

In the configuration of 8th also takes the circumferential width wc3 ' the third beveled section 334 gradually decreasing to zero in the direction toward the equatorial plane CL of the tire at or near the terminal end portion. Thus, the ground contact surface is in the area on the inside of the vehicle width direction of the central land portion 33 passing through the narrow circumferential groove 331 is defined and ensured, and the wet steering stability performance of the tire is ensured. It also takes a depth Hc3 (please refer 9 ) of the third beveled portion 334 gradually decreasing to zero in the direction toward the equatorial plane CL of the tire at or near the end portion.

Besides, as in 8th illustrates the circumferential width wc3 ' the third beveled section 334 preferably monotone from the terminal end portion of the third beveled portion 334 to the inside in the vehicle width direction towards. In particular, the circumferential width decreases wc3 'the third beveled section 334 from the terminal end section on the side of the equatorial plane CL the tire of the third chamfered portion 334 gradually to and from the middle section of the third beveled section 334 to the edge portion of the central web portion 33 on the inside in the vehicle width direction constant. In this way, the groove volume of the central lug groove decreases 332 from the inner portion of the central land portion 33 toward the inner side of the vehicle width direction, and the effect of improving the drainage characteristics of the central lug groove 334 over the third beveled section 334 will be raised.

It should be noted that in the configuration described above, the circumferential width wc3 ' the third beveled section 334 in the middle section of the third beveled section 334 is constant. However, no such limitation is intended and the circumferential width wc3 ' the third beveled section 334 can be from the final end section on the side of the equatorial plane CL of the tire to the edge portion of the central land portion 33 on the inside in the vehicle width direction continuously gradually increase (not illustrated).

As in the 2 and 3 is shown, the area on the outside in the vehicle width direction of the central land portion 33 passing through the narrow circumferential groove 331 is defined, a rib that is continuous in the tire circumferential direction and has a road contact surface with a smooth structure without grooves or fins. The road contact surface of such a smooth structure has a large ground contact surface as compared with a road contact surface having grooves or fins, thus contributing to the improvement of the dry steering stability performance of the tire. In particular, by the road contact surface of the planar structure, located on the equatorial plane of the tire CL the effect of improving the dry steering stability performance is significantly maintained. Also included in the configuration of 3 the inner area in the vehicle width direction of the central land portion 33 passing through the narrow circumferential groove 331 is defined, the central lug grooves 332 , the slats 333 and the beveled sections 334 , and the outer area in the vehicle width direction of the central land portion 33 includes the road contact surface having the above-described planar structure. Thus, the inner portion carries in the vehicle width direction of the central land portion 33 to the wet steering stability performance of the tire, and the outer portion in the vehicle width direction contributes to the dry steering stability performance of the tire. Accordingly, the wet steering stability performance and the dry steering stability performance of the tire are achieved in a compatible manner.

The road contact surface of the planar structure may, for example, have a small chamfered portion (not illustrated) extending along the edge portion of the land portion. Such a small chamfered portion generally has a width and depth of not more than 3.0 mm. In addition, the road contact surface of the planar structure may be provided with a surface finish (i.e., microtexture) formed of protrusions / grooves (not illustrated) of not more than 100 μm. With this configuration, the wet steering stability performance and the dry steering stability performance of the tire are achieved in a compatible and appropriate manner.

Besides, in the configuration of 2 the main circumferential groove 23 on the inside in the vehicle width direction, the central web section 33 defines a straight shape, and thus has the edge portion of the area that the road contact surface with the smooth structure of the central land portion 33 includes, a straight shape up. However, no such limitation is intended, and the major circumferential groove 23 forming the central bridge section 33 defined, may have a zigzag shape, a waveform or a step shape.

It should be noted that in the configuration of 2 the outer second web section 34 a second narrow circumferential groove 341 includes, which extends in the tire circumferential direction and through the narrow circumferential groove 341 divided in the tire transverse direction. In addition, an area is on the side of the equatorial plane CL the tire of the split outer second land portion 34 a rib containing a road contact surface with a smooth structure. Accordingly, the road contact surface of the area of the central land portion 33 on the outside in the vehicle width direction and the road contact surface of the outer second land portion 34 on the inside in the vehicle width direction, both a smooth structure. Thus, the dry steering stability performance of the tire is further increased.

Lug groove of the inner area

11 and 12 are explanatory diagrams corresponding to those in 2 illustrate illustrated louver groove. 11 FIG. 12 is a schematic view showing an example of a plurality of lug grooves. FIG 311 . 321 . 332 shows, which are arranged in the inner region in the vehicle width direction. 12 illustrates the positional relationship of the opening portions of the lug grooves 311 . 321 in the outermost circumferential groove 21 ,

In 2 includes an inner shoulder bridge section 31 a majority of the shoulder lug grooves 311 and a plurality of fins 312 ,

The shoulder lug grooves 311 each open at an end portion to the outermost Hauptumfangsrille 21 and extend in the tire transverse direction over the ground contact edge T of the tire. The shoulder lug grooves 311 are on extension lines of the continuous lug grooves 321 the inner second web portion 32 arranged and are inclined in the same direction as the continuous lug grooves 321 the inner second web portion 32 , The shoulder lug grooves 311 each close a beveled section 313 in an area within the ground contact margin T of the tire in the tire transverse direction. With this beveled section 313 becomes the groove volume of the shoulder lug groove 311 increased.

A groove width WG3 (Dimensional symbol omitted in drawings) of the shoulder lug groove 311 is set in the same way as the groove width W g1 the continuous lug grooves 321 the inner second web portion 32 , In particular, in the tread pattern of FIG 2 the shoulder lug grooves 311 narrow grooves, and the groove width WG3 the shoulder lug groove 311 and the groove width wm2 the main circumferential groove 22 (please refer 3 ) have the ratio 0.10 ≦ Wg3 / Wm2 ≦ 0.40. In addition, the groove width is WG3 the shoulder lug groove 311 preferably in the range of 1.1 mm ≦ Wg3 ≦ 2.5 mm and more preferably in the range of 1.2 mm ≦ Wg3 ≦ 1.9 mm. Thus, the groove width WG3 the shoulder lug groove 311 set appropriately. In other words, the drainage function of the shoulder lug grooves 311 ensured by the lower limit described above. In addition, with the upper limit described above, the groove width becomes WG3 the shoulder lug grooves 311 adjusted so that she is small. Thus, the groove surface of the inner Shoulder land portion 31 is reduced and the noise performance and the wet steering stability performance of the tire are improved.

In addition, the groove depth Hg3 (not illustrated) of the shoulder lug grooves 311 and the groove depth Hm (see 5 ) of the main circumferential groove 22 preferably the ratio 0.60 ≦ Hg3 / Hm ≦ 0.90. Thus, the groove depth becomes Hg3 the shoulder lug groove 311 set appropriately, and the noise performance and the wet steering stability performance of the tire are ensured.

The slats 312 are between shoulder grooves adjacent in the tire circumferential direction 311 . 311 arranged and open at an end portion to the outermost circumferential main groove 21 and extend in the tire transverse direction beyond the ground contact edge T of the tire. In addition, the shoulder lug grooves 311 and the slats 312 is alternately arranged at a predetermined interval in the tire circumferential direction. In the configuration of 2 becomes the inner shoulder bridge section 31 in the tire circumferential direction through the shoulder lug grooves 311 divided into a plurality of blocks (reference numerals omitted in the drawings). Each block contains a lamella 312 , The slats 312 extend parallel to the shoulder lug grooves 311 , In addition, a lamella 312 between the adjacent shoulder lug grooves 311 . 311 and the ground contact area of a block is substantially divided into two equal sections in the tire circumferential direction. Thus, the block rigidity is made uniform.

In the configuration of 2 form as in 11 illustrates the shoulder lug grooves 311 of the inner shoulder bridge section 31 , the continuous lug grooves 321 the inner second web portion 32 , and the central lug grooves 332 of the central footbridge section 33 the one lug groove, which is continuously from the bottom contact edge T of the tire towards the equatorial plane CL of the tire extends. In addition, the central web section includes 33 the narrow circumferential groove 331 extending in the tire circumferential direction and the central lug grooves 332 stand with the narrow circumferential groove 331 connect and end.

The conditions for configuring the plurality of lug grooves as a single, continuously extending lug groove are defined as follows. In particular, as in 12 Illustrated for a pair of lug grooves 311 . 321 on opposite sides of the main circumferential groove 21 the intersections between an extension line of the groove centerline of the lug groove 311 of the bridge section 31 and an extension line of the groove center line of the lug groove 321 of the bridge section 32 and the groove centerline of the circumferential main groove 21 covering the left and right bridge sections 31 . 32 defined as intersections S . T Are defined. In a configuration where an offset amount g of the intersections S, T in the tire circumferential direction and the pitch distance P (Pa, Pb, ...) (see 3 ) of the lug grooves 321 The relationship 0 ≤ g / P ≤ 0.20, the pair of opposing lug grooves 311 . 321 considered as consistent. In addition, the offset amount g is preferably in the range of 1.0 mm ≦ g ≦ 4.0 mm, and more preferably in the range of 2.0 mm ≦ g ≦ 3.0 mm.

In the configuration described above, (1) includes the central land portion 33 the narrow circumferential groove 331 extending in the tire circumferential direction; the central lug grooves 332 stand with the narrow circumferential groove 331 in connection; and the shoulder lug grooves 311 of the inner shoulder bridge section 31 , the continuous lug grooves 321 the inner second web portion 32 , and the central lug grooves 332 of the central footbridge section 33 form the one lug groove, which is continuously from the bottom contact edge T of the tire towards the equatorial plane CL of the tire extends. Thus, an efficient drainage channel from the central lug groove 332 to the ground contact margin T formed of the tire. Thus, the wet steering stability performance of the tire is improved. Also ( 2 ) is the central lug groove 332 with the narrow circumferential groove 331 of the central footbridge section 33 in contact and ends. Thus, the transmission of pattern noise to the outside in the vehicle width direction is suppressed compared to a configuration in which the lug grooves extend through the central land portion to the vehicle width direction outer area. Thus, the noise performance of the tire is improved.

For example, in the configuration of FIG 2 the lug groove coming from the three lug grooves 311 . 321 . 332 is formed, an arcuate shape with an inclination angle with respect to the tire circumferential direction, from the side of the equatorial plane CL of the tire towards the side of the ground contact edge T of the tire increases. Thus, the drainage properties of the central web portion 33 to the ground contact margin T of the tire increases.

As in 11 illustrates is the intersection between the lug groove ( 311 . 321 . 332 ) and the ground contact margin T of the tire as an intersection P Are defined. The intersection between the lug groove and the centerline of the inner second land portion 32 is as an intersection Q Are defined. The intersection of the narrow circumferential groove 331 of the central footbridge section 33 and the lug groove is as an intersection R Are defined.

This is a tilt angle φ1 a straight line PR with respect to the tire circumferential direction, preferably in the range of 50 degrees ≦ φ1 ≦ 75 degrees, and more preferably in the range of 55 degrees ≦ φ1 ≦ 70 degrees. As in 11 The position of the intersection Q of the inner second land portion is illustrated 32 in the tire circumferential direction between the intersection P and the point of intersection R arranged. Thus, the inclination angle becomes φ1 the lug groove made suitable.

The angle of inclination φ1 the straight line PR and a tilt angle φ2 a straight line QR with respect to the tire circumferential direction, preferably, the ratio φ2 ≤ φ1 and more preferably the ratio 10 degrees ≤ φ1-φ2. Furthermore, the angle of inclination is φ2 preferably in the range of 35 degrees ≤ φ2 ≤ 60 degrees and more preferably in the range of 40 degrees ≤ φ2 ≤ 55 degrees. Thus, the inclination angle becomes φ2 the lug groove made suitable.

Besides, as in 12 illustrates the intersections between the extension line of the groove center line of the shoulder lug groove 311 of the inner shoulder bridge section 31 and the extension line of the groove center line of the continuous lug groove 321 the inner second web portion 32 and the groove centerline of the circumferential main groove 21 covering the inner shoulder bridge section 31 and the inner second land portion 32 defined as the intersections S . T Are defined. In addition, the centers of the opening portions of the shoulder lug groove 311 and the continuous lug groove 321 to the main circumferential groove 21 as midpoints M . N Are defined.

Here are preferably the intersections S . T the groove centerlines of the lug grooves 311 . 321 by the predetermined offset amount G offset in the tire circumferential direction, and the positions in the tire circumferential direction of the centers M . N the opening portions of the lug grooves 311 . 321 are between the intersections S . T arranged. In such a configuration, the opening portion of the shoulder lug groove 311 and the opening portion of the continuous lug groove 321 substantially at the same position in the tire circumferential direction on opposite sides of the circumferential main groove 21 arranged. Thus, the water flow is made suitable when driving on wet road surfaces, and the wet steering stability performance of the tire is efficiently improved.

Groove area ratio between the inner area and the outer area
In 2 have a groove area ratio Gin of the ground contact area on the inside in the vehicle width direction of the equatorial plane CL of the tire and a groove area ratio G_out of the ground contact area on the outside in the vehicle width direction, the ratio 0.03 ≤ Gin - G_out ≤ 0.10, and more preferably the ratio 5.0% ≤ Gin - G_out ≤ 8.0%. In this way, the groove area ratio becomes Gin the inside in the vehicle width direction made suitable, and the transmission of pattern noise to the outside in the vehicle width direction is effectively suppressed.

The groove area ratio of the ground contact area in each ground contact area is defined as: groove area / (groove area + ground contact surface). "Groove area" refers to the opening area of the grooves on the ground contacting surface. Also, "groove" refers to the circumferential grooves and the lug grooves in the tread portion and does not include fins, kerfs and recess portions. "Ground Contact Surface" refers to the contact area between the tire and the road surface. In addition, the groove area and the ground contacting surface are measured at a contact surface between a tire and a flat plate when the tire is mounted on a predetermined rim, filled with the predetermined internal pressure, placed in a static state perpendicular to the flat plate and loaded with a load corresponding to the loaded load.

Modified examples

13 and 14 are explanatory diagrams corresponding to those in 12 illustrate illustrated louver groove. These drawings illustrate the positional relationship of the opening portions of the lug grooves 311 . 321 in the outermost circumferential groove 21 ,

In the configuration of 12 are the intersections S . T the groove centerlines of the lug grooves 311 . 321 by the predetermined offset amount G offset in the tire circumferential direction, and the positions in the tire circumferential direction of the centers M . N the opening portions of the lug grooves 311 . 321 are between the intersections S . T arranged. Such a configuration is preferable because the opening portions of the shoulder lug grooves 311 and the opening portions of the continuous lug grooves 321 are arranged at substantially the same position in the tire circumferential direction. Thus, the water flow is made suitable when driving on wet road surfaces, and the drainage characteristics are improved, so that the wet steering stability performance of the tire is efficiently improved.

In contrast, in the in 13 illustrated configuration the intersections S . T the groove centerlines of the lug grooves 311 . 321 arranged at the same position in the tire circumferential direction. Accordingly, the extension line of the groove center line of the shoulder lug groove is aligned 311 of the inner shoulder bridge section 31 with the extension line of the groove center line of the continuous lug groove 321 the inner second web portion 32 ,

In the configuration of 14 are the intersections S . T the groove centerlines of the lug grooves 311 . 321 by the predetermined offset amount G offset in the tire circumferential direction, and the positions in the tire circumferential direction of the centers M . N the opening portions of the lug grooves 311 . 321 are outside the intersections S . T arranged.

effects

As described above, the pneumatic tire closes 1 a mounting direction indicating section (not illustrated) indicating the mounting direction of the tire with respect to the vehicle. In addition, the pneumatic tire closes 1 two or more main circumferential grooves 21 . 22 in the area on the inside in the vehicle width direction of the equatorial plane CL of the tire and extending in the tire circumferential direction, and includes three or more web portions 31 to 33 one through the main circumferential grooves 21 . 22 are defined and formed (see 2 ). The inner shoulder bridge section 31 closes shoulder lug grooves 311 in, which extend in the tire transverse direction. In addition, all inner second web sections close 32 (a single in 2 ) in each case the continuous lug groove 321 in the tire transverse direction through the inner second web portion 32 extends. The central bridge section 33 closes a narrow circumferential groove 331 a, which extends in the tire circumferential direction, and central lug grooves 332 each at an end portion to the edge portion on the inside in the vehicle width direction of the central land portion 33 open and terminate at the other end portion and with the narrow circumferential groove 331 stay in contact. The shoulder lug grooves 311 , the continuous lug grooves 321 and the central lug grooves 332 form a single lug groove extending continuously from the ground contact edge T of the tire to the equatorial plane CL of the tire.

In the configuration described above, (1) includes the central land portion 33 the narrow circumferential groove 331 extending in the tire circumferential direction; the central lug grooves 332 stand with the narrow circumferential groove 331 in connection; and the shoulder lug grooves 311 of the inner shoulder bridge section 31 , the continuous lug grooves 321 the inner second web portion 32 , and the central lug grooves 332 of the central footbridge section 33 form the one lug groove, which is continuously from the bottom contact edge T of the tire towards the equatorial plane CL of the tire extends. Thus, an efficient drainage channel from the central lug groove 332 to the ground contact margin T formed of the tire. This has the advantage of improving the wet steering stability performance of the tire. Also ( 2 ) is the central lug groove 332 with the narrow circumferential groove 331 of the central footbridge section 33 in contact and ends. Thus, the transmission of pattern noise to the outside in the vehicle width direction is suppressed compared to a configuration in which the lug grooves extend through the central land portion to the vehicle width direction outer area. This is advantageous because the noise performance of the tire is improved.

Also, in the pneumatic tire 1 the continuous lug grooves 321 the inner second web portion 32 in the tire circumferential direction with predetermined pitch distances P ( Pa . pb , ...) arranged (see 3 ). In addition, the offset amount G in the tire circumferential direction of the intersections S . T the groove centerlines of the shoulder lug groove 311 and the continuous lug groove 321 and the pitch distance P the shoulder lug grooves 311 the ratio 0 ≦ g / P ≦ 0.20 (see 12 ). This is advantageous in that the pair of opposing lug grooves 311 . 321 extends suitably throughout and the function of the lug groove is suitably ensured.

Besides, the pneumatic tire is 1 with a single inner second bridge section 32 provided (see 2 ). The intersection between the lug groove and the ground contact edge T of the tire is considered the point of intersection P defines the intersection between the lug groove and the centerline of the inner second land portion 32 is as the intersection Q defined, and the angle of inclination φ1 the straight line PR with respect to the tire circumferential direction is in the range of 50 degrees ≤ φ1 ≤ 75 degrees (see 11 ). This is advantageous in that the angle of inclination φ1 the lug groove is made suitable. In other words, the lower limit described above ensures the effect of improving the drainage characteristics due to the inclination of the lug groove. In addition, the above-described upper limit suppresses deterioration of the noise performance caused by an excessive extension length of the lug groove.

In addition, in the pneumatic tire 1 the intersection between the lug groove and the centerline of the inner second land portion 32 as the intersection Q defined, the intersection between the narrow circumferential groove 331 of the central footbridge section 33 and the lug groove is as the intersection R defined, and the angle of inclination φ1 the straight line PR and the angle of inclination φ2 the straight line QR with respect to the tire circumferential direction, the conditions satisfy φ2 ≤ φ1 and 35 degrees ≤ φ2 ≤ 60 degrees (see FIG 11 ). This is advantageous in that the angle of inclination φ2 the lug groove is made suitable. In other words, the lower limit described above ensures the effect of improving the drainage characteristics due to the inclination of the lug groove. In addition, the above-described upper limit suppresses deterioration of the noise performance caused by an excessive extension length of the lug groove.

In addition, in the pneumatic tire 1 according to an embodiment of the invention, the position of the point of intersection Q in the tire circumferential direction between the intersection P and the point of intersection R arranged (see 11 ). This is advantageous in that the drainage characteristics of the lug groove are efficiently improved.

At the pneumatic tire 1 The lug groove has an arcuate shape with an inclination angle with respect to the tire circumferential direction, that of the side of the equatorial plane CL of the tire to the side of the ground contact edge T of the tire increases (see 11 ). This is advantageous in that the drainage characteristics of the lug groove are efficiently improved.

In addition, in the pneumatic tire 1 the narrow circumferential groove 331 of the central footbridge section 33 in relation to the equatorial plane CL of the tire on the inside offset in the vehicle width direction (see 11 ). This is advantageous in that the through the narrow circumferential groove 331 provided outflow function is improved.

At the pneumatic tire 1 have the distance ds from the edge portion of the central land portion 33 on the inside in the vehicle width direction to the groove center line of the narrow circumferential groove 331 and the width W2 of the central footbridge section 33 preferably the ratio 0.25 ≦ Ds / W2 ≦ 0.45 (see 8th ). This is advantageous in that the position of the narrow circumferential groove 331 is made suitable. In other words, with the lower limit described above, the groove width Ws becomes the narrow circumferential groove 331 ensured, and the drainage function of the narrow circumferential groove 331 is ensured. In addition, the upper limit described above suppresses a decrease in the rigidity of the central land portion 33 caused by the arrangement of the narrow circumferential groove 331 is caused.

Besides, with the pneumatic tire 1 the groove width W g1 (please refer 4 ) of the continuous lug grooves 321 the inner second web portion 32 and the groove width wm2 (please refer 3 ) of the main circumferential groove 22 on the side of the equatorial plane CL of the tire, the inner second web portion 32 defines the ratio 0.10 ≦ Wg1 / Wm2 ≦ 0.40. This is advantageous in that the groove width W g1 the continuous lug groove 321 is set appropriately. In other words, the drainage function of the continuous lug groove 321 ensured by the lower limit described above. In addition, with the upper limit described above, the groove width becomes W g1 the continuous lug grooves 321 adjusted so that she is small. Thus, the groove area of the inner second land portion becomes 32 is reduced and the noise performance and the wet steering stability performance of the tire are improved.

Besides, with the pneumatic tire 1 the groove width Ws (see 8th ) of the narrow circumferential groove 331 of the central footbridge section 33 and the groove width wm2 (please refer 3 ) of the main circumferential groove 22 on the inside in the vehicle width direction, the central web section 33 defines the ratio 0.20 ≤ Ws / Wm2 ≤ 0.50. This is advantageous in that the groove width Ws of the narrow circumferential groove 331 of the central footbridge section 33 is made suitable. In other words, with the lower limit described above, the groove width Ws becomes the narrow circumferential groove 331 ensured, and the drainage function of the narrow circumferential groove 331 is ensured. In addition, the upper limit described above suppresses a decrease in the rigidity of the central land portion 33 caused by the arrangement of the narrow circumferential groove 331 is caused.

Besides, with the pneumatic tire 1 the groove depth hg1 the continuous lug grooves 321 the inner second web portion 32 and the groove depth Hm of the main circumferential groove 22 on the side of the equatorial plane CL of the tire, the inner second web portion 32 defines the ratio 0.60 ≤ Hg1 / Hm ≤ 0.90 (see 5 ). This is advantageous in that the groove depth hg1 the continuous lug groove 321 is set appropriately. In other words, with the lower limit described above, the groove depth becomes hg1 the continuous lug groove 321 ensured, and the drainage properties of the continuous lug groove 321 be ensured. In addition, with the upper limit described above, the groove depth becomes hg1 the continuous lug groove 321 adjusted so that she is small. Thus, the groove volume of the inner second land portion becomes 32 reduced, and the noise performance and the wet steering stability performance of the tire are ensured.

Besides, with the pneumatic tire 1 the groove depth hs the narrow circumferential groove 331 of the central footbridge section 33 and the groove depth Hm the main circumferential groove 22 on the inside in the vehicle width direction, the central web section 33 defines the ratio 0.60 ≤ Hs / Hm ≤ 0.90 (see 9 ). This is advantageous in that the groove depth hs the narrow circumferential groove 331 is made suitable. In other words, with the lower limit described above, the groove depth becomes hs the narrow circumferential groove 331 ensured, and the drainage function of the narrow circumferential groove 331 is ensured. In addition, the upper limit described above suppresses a decrease in the rigidity of the central land portion 33 caused by the arrangement of the narrow circumferential groove 331 is caused.

Also, in the pneumatic tire 1 the intersections between the extension line of the groove center line of the shoulder lug groove 311 of the inner shoulder bridge section 31 and the extension line of the groove center line of the continuous lug groove 321 the inner second web portion 32 and the groove centerline of the circumferential main groove 22 covering the inner shoulder bridge section 31 defined as the intersections S . T Are defined; the centers of the opening portions to the main circumferential groove 22 the shoulder lug groove 311 and the continuous lug groove 321 are as centers M . N Are defined; and the positions in the tire circumferential direction of the centers M . N are between the intersections S . T arranged (see 12 ). Such a configuration is advantageous in that since the opening portions of the shoulder lug grooves 311 and the opening portions of the continuous lug grooves 321 are arranged at substantially the same position in the tire circumferential direction, the water flow is made suitable when driving on wet road surfaces and the drainage properties are improved, so that the wet steering stability performance of the tire is efficiently improved.

At the pneumatic tire 1 the area on the outside in the vehicle width direction of the central web section closes 33 passing through the narrow circumferential groove 331 is defined, a road contact surface with a smooth structure without grooves or lamellae (see 2 ). This is advantageous in that the ground contacting surface of the outer area in the vehicle width direction of the central land portion 33 is ensured and the dry steering stability performance of the tire is ensured.

At the pneumatic tire 1 have the groove area ratio Gin of the ground contact area on the inside in the vehicle width direction of the equatorial plane CL of the tire and the groove area ratio G_out of the ground contact area on the outside in the vehicle width direction, the ratio 0.03 ≦ G_in - G_out ≦ 0.10 (see 2 ). This has the advantage that the groove area ratio Gin of the inner region is suitably set in the vehicle width direction. In other words, with the lower limit described above, the groove area ratio becomes Gin of the inner portion in the vehicle width direction is set to be relatively large, and the wet performance of the tire is ensured. In addition, with the lower limit described above, the transmission of pattern noise to the outside in the vehicle width direction by an excessive groove area ratio Gin of the inner area in the vehicle width direction is effectively suppressed.

Examples

15 FIG. 11 is a table showing results of performance tests of pneumatic tires according to embodiments of the invention. FIG.

In the performance tests, a plurality of different test tires were evaluated for (1) wet steering stability performance and (2) noise performance. Test tires with a tire size of 215 / 55R17 94W were mounted on rims with a rim size of 17x17JJ, set at an air pressure of 230 kPa and loaded with the load specified by JATMA. Then the test tires were mounted on all four wheels of the test vehicle, which was a 1.6-liter passenger vehicle with front-engine and front-wheel drive (FF).

(1) In the evaluation of the wet steering stability performance, the test vehicle was run on an asphalt road covered with 1 mm of water at 40 km / h. Then, the test driver made a sensory evaluation regarding steering in lane change and cornering, and stability in forward driving. The results of the evaluation are expressed as index values and using the example of the prior art as the reference value ( 100 ) rated. Higher values are to be preferred in this evaluation.

(2) In the noise performance evaluation, the test vehicle was run at a speed of 60 km / h on a test track according to the International Organization for Standardization (ISO), which was a dry road surface, and the sound pressure level (dB ) of the pass-by noise (vehicle outside noise) was measured at a position 7.5 m away from the track. The differences in dB between the measurement results and the measurement value of the example of the prior art are calculated, and the measurement results are evaluated. Lower values are to be preferred in this evaluation.

The test tires of Examples 1 to 13 have the configuration of 1 to 3 on, and the shoulder lug grooves 311 of the inner shoulder bridge section 31 , the continuous lug grooves 321 the inner second web portion 32 and the central lug grooves 332 of the central footbridge section 33 form a single lug groove extending continuously from the ground contact edge of the tire to the equatorial plane of the tire. There are also the central lug grooves 332 with the narrow circumferential groove 331 of the central footbridge section 33 in connection. In addition, the width is W1 the inner second web portion 32 21 mm, and the width W2 of the central footbridge section 33 is 26 mm. In addition, the groove width is wm2 the main circumferential groove 22 7.5 mm, and the groove depth Hm is 8.3 mm. In addition, the groove width Ws is the narrow circumferential groove 331 2.2 mm, and the groove depth Hs is 5.8 mm. The groove depth hg1 the continuous lug groove 321 is 6.6 mm, and the groove depth hg2 the central lug groove 332 is 5.3 mm.

The test tire of the prior art example has the configuration of Example 1 except that the lug grooves of each of the land portions 31 to 33 do not extend consistently and the central bridge section 33 does not include a narrow circumferential groove.

As apparent from the test results, the test tires of Examples 1 to 13 can provide wet steering stability performance and noise performance in a compatible manner.

LIST OF REFERENCE NUMBERS

1:

tire

11:

bead

12:

bead filler

13:

carcass

14:

belt layer

141, 142:

cross belt

143:

belt cover

15:

Tread rubber

16:

Sidewall rubber

17:

Radkranzpolstergummi

21 to 24:

Main circumferential groove

31 to 35:

web section

311, 321, 332:

lug groove

312, 322, 333:

lamella

323, 324, 334:

Beveled section

331:

Narrow circumferential groove

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2013052736 A [0003]

Claims (15)

A pneumatic tire comprising: a mounting direction indicating portion indicating a mounting direction of the pneumatic tire with respect to a vehicle; two or more main circumferential grooves arranged in an area on an inside in the vehicle width direction of an equatorial plane of the tire and extending in the tire circumferential direction; and three or more land portions defined and formed by the two or more circumferential main grooves; wherein the web-inwardmost land portion is defined as an inner shoulder land portion, the land portion disposed on the equatorial plane of the tire being defined as a central land portion, wherein one or more land portions disposed between the inner shoulder land portion and the central land portion; are defined as an inner second land portion; wherein the inner shoulder land portion includes a shoulder lug groove extending in the tire transverse direction; wherein the one or more inner second land portions comprise a continuous lug groove extending in the tire transverse direction through the inner second land portion; wherein the central land portion includes a single narrow circumferential groove extending in the tire circumferential direction and a central lug groove opening at an end portion to an edge portion of the central land portion in the vehicle width direction inside and terminating at another end portion and having the narrow circumferential groove in FIG Connection stands; and wherein the shoulder lug groove, the continuous lug groove and the central lug groove form a single lug groove extending continuously from a ground contact edge of the tire to the equatorial plane of the tire. Pneumatic tires Claim 1 wherein a plurality of the continuous lug grooves of the inner second land portion are arranged in the tire circumferential direction with a predetermined pitch distance P; Intersections between an extension line of a groove center line of the shoulder lug groove of the inner shoulder land portion and an extension line of a groove center line of the continuous lug groove of the inner second land portion and a groove center line of the main circumferential groove defining the inner shoulder land portion and the inner second land portion are defined as intersections S, T; and an offset amount g in the tire circumferential direction of the intersection points S, T and a pitch pitch P of the shoulder lug groove have a ratio of 0 ≦ g / P ≦ 0.20. Pneumatic tires Claim 1 or 2 wherein a single inner second land portion is provided; an intersection between the connection lug groove and the ground contact edge of the tire is defined as an intersection P, and an intersection between the connection lug groove and a center line of the inner second land portion is defined as an intersection point Q; and an inclination angle φ1 of a straight line PR with respect to the tire circumferential direction is in a range of 50 degrees ≤ φ1 ≤ 75 degrees. Pneumatic tires Claim 3 wherein the intersection between the lug groove and the centerline of the inner second land portion is defined as the intersection Q and an intersection between the narrow circumferential groove of the central land portion and the lug groove is defined as intersection R; and the inclination angle φ1 of the straight line PR and an inclination angle φ2 of a straight line QR with respect to the tire circumferential direction satisfy the conditions φ2 ≤ φ1 and 35 degrees ≤ φ2 ≤ 60 degrees. Pneumatic tires Claim 4 wherein a position in the tire circumferential direction of the intersection point Q is disposed between the intersection P and the intersection point R. Pneumatic tires after one of Claims 1 to 5 wherein the lug groove has an arcuate shape having an inclination angle with respect to the tire circumferential direction, which increases from the equatorial plane side of the tire toward the tire ground contact edge side of the tire. Pneumatic tires after one of Claims 1 to 6 wherein the narrow circumferential groove of the central land portion is staggered with respect to the equatorial plane of the tire on the inside in the vehicle width direction. Pneumatic tires after one of Claims 1 to 7 wherein a distance Ds from the edge portion of the central land portion on the vehicle widthwise inner side to a groove centerline of the narrow circumferential groove and a width W2 of the central land portion have a ratio 0.25 ≦ Ds / W2 ≦ 0.45. Pneumatic tires after one of Claims 1 to 8th wherein a groove width Wg1 of the continuous lug groove of the inner second land portion and a groove width Wm2 of the circumferential circumferential groove on the side of the equatorial plane of the tire defining the inner second land portion have a ratio of 0.10 ≦ Wg1 / Wm2 ≦ 0.40. Pneumatic tires after one of Claims 1 to 9 wherein a groove width Ws of the narrow circumferential groove of the central land portion and a groove width Wm2 of the main circumferential groove on the vehicle width direction inner side defining the central land portion have a ratio of 0.20 ≦ Ws / Wm2 ≦ 0.50. Pneumatic tires after one of Claims 1 to 10 wherein a groove depth Hg1 of the continuous lug groove of the inner second land portion and a groove depth Hm of the circumferential circumferential groove on the side of the equatorial plane of the tire defining the inner second land portion have a ratio of 0.60 ≦ Hg1 / Hm ≦ 0.90. Pneumatic tires after one of Claims 1 to 11 wherein a groove depth Hs of the narrow circumferential groove of the central land portion and a groove depth Hm of the main circumferential groove on the vehicle width direction inner side defining the central land portion have a ratio of 0.60 ≦ Hs / Hm ≦ 0.90. Pneumatic tires after one of Claims 1 to 12 wherein intersections between an extension line of a groove center line of the shoulder lug groove of the inner shoulder land portion and an extension line of a groove center line of the continuous lug groove of the inner second land portion and a groove center line of the main circumferential groove defining the inner shoulder land portion are defined as intersections S, T; Center points of opening portions to the main circumferential groove of the shoulder lug groove and the continuous lug groove are defined as centers M, N; and positions in the tire circumferential direction of the centers M, N between the intersections S, T are arranged. Pneumatic tires after one of Claims 1 to 13 wherein a region on the vehicle width direction outer side of the central land portion defined by the narrow circumferential groove includes a road contact surface having a smooth structure without a groove or a sipe. Pneumatic tires after one of Claims 1 to 14 wherein a groove area ratio G_in of a ground contact area on the vehicle width direction inside of the equatorial plane of the tire and a groove area ratio G_out of a ground contact area on the vehicle width direction outside have a ratio of 0.03 ≦ G_in - G_out ≦ 0.10.

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